dudgeon



I (No Model.) v

; 'R. H.'DUDGEON.

' HYDRAULIC JACK;

ATTORNEY 0 be n 4 H .y no. 1| 6 WITNESSES:

UNITED STATES PATENT.-. QFFIcn.

RICHARD H. DUDGEON, OF NEW YORK, N. Y., ASSIGNOR TO RICHARD DUDGEON, OF SAME PLACE. I

' HYDRAULIC JACK.

SPECIFICATION forming part of Letters Patent No. 297,975, dated May 6, 1884.

7 Application filed May 10, 188 3. (No model.) 7

To all whom it may concern:

Be it known that I, RIoHAjRD H. DUDGEON, a citizen of the United States, residingin the city, county, and State of New York, have invented certain new and useful Improvements in Hydraulic Jacks, of which the following is a specification.

My invention relates to improvements in hydraulic jacks; and it relates particularly to the arrangement and construction of the hollow piston and the passages therein; and the object of my invention is to construct hydraulic jacks having great durability, combined with rapidity of action.

The nature of my invention will be fully explained by reference to the accompanying specification and the drawings annexed, which form part of the same.

Referring to the drawings, Figure 1 is a central vertical section of so much of a hydraulic jack as is necessary to illustrate my invention. Figs. 2, 3, 4, and 5 are detail views of the parts separately, and Fig. 6 represents a modification of the internal cylinder.

In each of the views similar letters of reference indicate corresponding parts wherever they occur. V

A represents a portion of the piston-cylin der, and B the hollow piston, which is bored out at b to receive an independent internal cylinder, 0, in which the plunger D operates. The internal independent cylinder, 0, is provided with a series of liquid-passages, c, bored or otherwise formed in the body of the annular metallic casting of which it is composed. The internal cylinder, 0, is held in place in the hollow piston B by means of avalve block or plug, E, screwed into the hollow piston by means of a key or driver adapted to be received into the recesses e e, or by other suitable means. -Onits under side the block or plug E is formed with a circular extension, which is tapped to receive a nut or bindingpiece, F, for the purpose of supporting and holding the packing G properly in position.

In the center of the block or plug E, I form,

an aperture, 6, in which is arranged a valve shaft, e, formed on its lower end with a conical valve, e The valve 6 and its stem e are held in position by'means of a coiled or other suitable spring, e, which is held in position by means of a bearing plate or plug, H,which is tapped with a screw-thread, h, adapted to be received into a corresponding thread in the under side of the nut or binding-piece F.

In the center of the plate or plug H, I form a slot or opening, I), for the passage to and .fro of the liquid, as regulated by the valve e In the upper side of the valve block or plug E, I form a dish-shaped cavity,which not only serves as a means of communication to the passages 'c of the cylinder 0, but also allows of the valve stem or shaft 6 protruding above the surface of the block or plug E in position to be depressed by the plunger when it is desired to allow the fluid to flow back after the jack has been used, orwhen it is from any cause desired to lower the piston and parts connected therewith. In the block or plug E is formed a passage or passages, by means of which the liquid is conducted to and from the upper and lower portions of the cylinder as regulated or controlled by valve 6.

The operation of the device is as follows: When it is desired to operate the jack for the purpose of raising a body or superincumbent weight, the plunger D may be operated to and consequently proportionately raise the same. When the jack has been raised to the desired height, a greater extent of stroke is imparted to the plunger D, such that it shall at each downward motion depress the shaft or stem 0, of the valve c and thereby allowof the liquid returning through the passages c to the upper cavity of the cylinder 0, thereby causing the lowering of the piston B and its superincunibent load.

In Fig. 6 I have shown the passages c in 2. The combination, with the hollow piston B and independent cylinder 0, provided with 15 internal fluid-passages, c, of the valve block or plug E, valve 0', and a packing, G, and nut or binding-piece F, substantially as shown and described.

\Vitness my hand this 3d day of April, A. 20 D. 1883.

RICHARD H. DUDGEON.

Witnesses:

WILLIs DICDONALD, J. E. WARNER. 

